Encapsulation of N. gonorrhoeae was demonstrated in 1977. This project is directed at purifying, characterizing, and serotyping gonococcal capsules so that the capsule's role in the pathogenesis of gonococcal disease and the feasibility of a capsular vaccine can be determined. Alcian blue dye, which stains acidic polysaccharide, has been employed for detection of capsular substance. Gonococcal strains, media, and growth conditions which were optimal for production of capsule were selected using this dye in the electron microscope. A soluble acidic polysaccharide (SAP) removed from the surface of gonococci by gentle manipulation has been located with Alcian blue in a polyacrylamide tube gel assay. SAP, which is a large molecular weight polysaccharide, migrates in the tube gel system in a fashion similar to meningococcal capsular polysaccharide. During the proposed project period, pure capsular substance will be prepared so that biochemical characterization and serotyping of gonococcal capsules can be done. Four methods will be tested for usefulness in purifying gonococcal SAP in workable quantities. SAP will be traced during purification with the tube gel assay. Purified SAP will be tested for purity by determining that it is free of protein, nucleic acid, LPS, and media components. Biochemical characterization of purified SAP will be done by determining component sugars and concentrations by gas-liquid chromatography and sequencing by the Smith degradation procedure. This will allow comparison of chemical structure to other capsular and non-capsular polysaccharides. For confirmation that SAP corresponds to a morphologic capsule, gonococci exposed to antibody against pure SAP will be examined in the electron microscope to determine whether this antibody stains the capsule. Finally, serotyping of gonococcal capsules will be done with fluorescent antibody techniques employing antisera against encapsulated organisms made capsule-specific by adsorption or antiserum against pure SAP when it is available.